The present invention relates to a method of manufacturing an electro-optical device in which self-emitting elements constitute a plurality of pixels, the electro-optical device manufactured by the method, and an electronic apparatus using the same.
In recent years, in addition to light-receiving type liquid crystal display devices, organic electroluminescent (hereinafter, referred to as EL) display devices having thickness reduction, weight reduction, and no viewing angle dependency have attracted considerable attention as self-emitting electro-optical devices. In these organic EL display devices, a display substrate in which a pixel switching element and an organic EL element are arranged in each of a plurality of pixels arranged in a matrix like liquid crystal is used, and display is performed by controlling an ON or OFF state of each pixel. The organic EL element comprises two electrodes and an organic material interposed between the two electrodes that contributes to the emission of light. When electrons and holes are injected from the two electrodes to the light-emitting material each pixel emits light. That is, when the electrons and holes injected from the electrodes are recombined at the light-emitting center of the organic material, organic molecules is in an excited state. Then, when the organic molecules return to a normal state from the excited state, the organic molecules emit light. Therefore, when materials having different emission colors are used, it is possible to display a color image.
When a large organic EL display device having a size larger than 30 inches is required, similar to a liquid crystal display device, a large substrate should grow in size. Therefore, a manufacturing line for the pixel switching TFTs (thin film transistors) becomes large in scale. In addition, the increase in the size of the substrate causes the reduction in yield in a cleaning process or a film forming process. Further, when the TFTs are composed of low-temperature polysilicon TFTs in order to use a low-priced glass substrate as the substrate, a laser annealing process for crystallizing amorphous silicon into polysilicon is unstably performed.
Therefore, there has been proposed a technique of constituting a large organic EL display device by arranging a plurality of substrates in a plane, which have the size enough to be realized by the conventional technique. As such a technique of constituting the large organic EL display device, the following methods have been proposed: a method in which, after pixel switching elements and organic EL elements are formed on a small substrate, a plurality of the small substrates are arranged in a plane; and a method in which, after pixel switching elements are formed on a small substrate, a plurality of the small substrates are arranged in a plane, and organic EL elements are then formed on each of the small substrates. In the latter case, there is an advantage in which a joint between the small substrates is invisible (for example, see Patent Documents 1 and 2).
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2001-102171.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2002-297063